Start and stop of reception of downlink transmission based on paging

ABSTRACT

A method and apparatus for start and stop of reception of downlink (DL) transmission based on a paging in a wireless communication system is provided. A wireless device, upon receiving a paging, resumes a radio bearer in an idle state (e.g., RRC_IDLE) and/or an inactive state (e.g., RRC_INACTIVE).

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119 (e), this application claims the benefit of Korean Patent Applications No. 10-2019-0051118, filed on May 1, 2019 and No. 10-2019-0051120, filed on May 1, 2019, the contents of which are all hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to a start and stop of reception of downlink (DL) transmission based on a paging.

BACKGROUND

3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPP to develop requirements and specifications for new radio (NR) systems. 3GPP has to identify and develop the technology components needed for successfully standardizing the new RAT timely satisfying both the urgent market needs, and the more long-term requirements set forth by the ITU radio communication sector (ITU-R) international mobile telecommunications (IMT)-2020 process. Further, the NR should be able to use any spectrum band ranging at least up to 100 GHz that may be made available for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usage scenarios, requirements and deployment scenarios including enhanced mobile broadband (eMBB), massive machine-type-communications (mMTC), ultra-reliable and low latency communications (URLLC), etc. The NR shall be inherently forward compatible.

To meet the more stringent requirements of future 5G use cases, it will soon be necessary to reduce UL latency even further. Early data transmission (EDT) is a feature that would allow opportunistic data transmission to commence during the connection resume procedure. EDT has already been introduced in LTE machine-type communication (LTE-M) and narrowband internet-of-things (NB-IoT), where traffic is expected to comprise the transmission of small amounts of data and one of the primary objectives is long user equipment (UE) battery life. For use cases where traffic consists of only one uplink (UL) and/or one downlink (DL) data packet, EDT improves energy efficiency by enabling the network to release the UE to the inactive state without the need for intermediate resume and resume complete messages.

SUMMARY

An aspect of the present disclosure is to provide a method and apparatus for start and stop of reception of downlink (DL) transmission based on a paging.

Another aspect of the present disclosure is to provide a method and apparatus for radio bearer handling when data transmission is performed in an idle state (e.g., RRC_IDLE) and/or an inactive state (e.g., RRC_INACTIVE).

In an aspect, a method for a wireless device in a wireless communication system is provided. The method includes, upon receiving a paging, resuming a radio bearer in an idle state and/or an inactive state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

FIG. 3 shows an example of a wireless device to which implementations of the present disclosure is applied.

FIG. 4 shows another example of wireless devices to which implementations of the present disclosure is applied.

FIG. 5 shows an example of UE to which implementations of the present disclosure is applied.

FIGS. 6 and 7 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

FIG. 8 shows a frame structure in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

FIG. 9 shows a data flow example in the 3GPP NR system to which implementations of the present disclosure is applied.

FIG. 10 shows an example of PDSCH time domain resource allocation by PDCCH to which implementations of the present disclosure is applied.

FIG. 11 shows an example of PUSCH time resource allocation by PDCCH to which implementations of the present disclosure is applied.

FIG. 12 shows an example of physical layer processing at a transmitting side to which implementations of the present disclosure is applied.

FIG. 13 shows an example of physical layer processing at a receiving side to which implementations of the present disclosure is applied.

FIG. 14 shows an example of a method for a wireless device to which implementations of the present disclosure is applied.

FIG. 15 shows an example of a method for performing data transmission for a UE in RRC_IDLE and/or RRC_INACTIVE to which implementations of the present disclosure is applied.

FIG. 16 shows an example of downlink data transmissions for a UE in RRC_IDLE and/or RRC_INACTIVE to which implementations of the present disclosure is applied.

DETAILED DESCRIPTION

The following techniques, apparatuses, and systems may be applied to a variety of wireless multiple access systems. Examples of the multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (SC-FDMA) system, and a multicarrier frequency division multiple access (MC-FDMA) system. CDMA may be embodied through radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be embodied through radio technology such as global system for mobile communications (GSM), general packet radio service (GPRS), or enhanced data rates for GSM evolution (EDGE). OFDMA may be embodied through radio technology such as institute of electrical and electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is a part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolved version of 3GPP LTE.

For convenience of description, implementations of the present disclosure are mainly described in regards to a 3GPP based wireless communication system. However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP based wireless communication system, aspects of the present disclosure that are not limited to 3GPP based wireless communication system are applicable to other mobile communication systems.

For terms and technologies which are not specifically described among the terms of and technologies employed in the present disclosure, the wireless communication standard documents published before the present disclosure may be referenced.

In the present disclosure, “A or B” may mean “only A”, “only B”, or “both A and B”. In other words, “A or B” in the present disclosure may be interpreted as “A and/or B”. For example, “A, B or C” in the present disclosure may mean “only A”, “only B”, “only C”, or “any combination of A, B and C”.

In the present disclosure, slash (/) or comma (,) may mean “and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B or C”.

In the present disclosure, “at least one of A and B” may mean “only A”, “only B” or “both A and B”. In addition, the expression “at least one of A or B” or “at least one of A and/or B” in the present disclosure may be interpreted as same as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. In addition, “at least one of A, B or C” or “at least one of A, B and/or C” may mean “at least one of A, B and C”.

Also, parentheses used in the present disclosure may mean “for example”. In detail, when it is shown as “control information (PDCCH)”, “PDCCH” may be proposed as an example of “control information”. In other words, “control information” in the present disclosure is not limited to “PDCCH”, and “PDDCH” may be proposed as an example of “control information”. In addition, even when shown as “control information (i.e., PDCCH)”, “PDCCH” may be proposed as an example of “control information”.

Technical features that are separately described in one drawing in the present disclosure may be implemented separately or simultaneously.

Although not limited thereto, various descriptions, functions, procedures, suggestions, methods and/or operational flowcharts of the present disclosure disclosed herein can be applied to various fields requiring wireless communication and/or connection (e.g., 5G) between devices.

Hereinafter, the present disclosure will be described in more detail with reference to drawings. The same reference numerals in the following drawings and/or descriptions may refer to the same and/or corresponding hardware blocks, software blocks, and/or functional blocks unless otherwise indicated.

FIG. 1 shows an example of a communication system to which implementations of the present disclosure is applied.

The 5G usage scenarios shown in FIG. 1 are only exemplary, and the technical features of the present disclosure can be applied to other 5G usage scenarios which are not shown in FIG. 1.

Three main requirement categories for 5G include (1) a category of enhanced mobile broadband (eMBB), (2) a category of massive machine type communication (mMTC), and (3) a category of ultra-reliable and low latency communications (URLLC).

Partial use cases may require a plurality of categories for optimization and other use cases may focus only upon one key performance indicator (KPI). 5G supports such various use cases using a flexible and reliable method.

eMBB far surpasses basic mobile Internet access and covers abundant bidirectional work and media and entertainment applications in cloud and augmented reality. Data is one of 5G core motive forces and, in a 5G era, a dedicated voice service may not be provided for the first time. In 5G, it is expected that voice will be simply processed as an application program using data connection provided by a communication system. Main causes for increased traffic volume are due to an increase in the size of content and an increase in the number of applications requiring high data transmission rate. A streaming service (of audio and video), conversational video, and mobile Internet access will be more widely used as more devices are connected to the Internet. These many application programs require connectivity of an always turned-on state in order to push real-time information and alarm for users. Cloud storage and applications are rapidly increasing in a mobile communication platform and may be applied to both work and entertainment. The cloud storage is a special use case which accelerates growth of uplink data transmission rate. 5G is also used for remote work of cloud. When a tactile interface is used, 5G demands much lower end-to-end latency to maintain user good experience. Entertainment, for example, cloud gaming and video streaming, is another core element which increases demand for mobile broadband capability. Entertainment is essential for a smartphone and a tablet in any place including high mobility environments such as a train, a vehicle, and an airplane. Other use cases are augmented reality for entertainment and information search. In this case, the augmented reality requires very low latency and instantaneous data volume.

In addition, one of the most expected 5G use cases relates a function capable of smoothly connecting embedded sensors in all fields, i.e., mMTC. It is expected that the number of potential Internet-of-things (IoT) devices will reach 204 hundred million up to the year of 2020. An industrial IoT is one of categories of performing a main role enabling a smart city, asset tracking, smart utility, agriculture, and security infrastructure through 5G.

URLLC includes a new service that will change industry through remote control of main infrastructure and an ultra-reliable/available low-latency link such as a self-driving vehicle. A level of reliability and latency is essential to control a smart grid, automatize industry, achieve robotics, and control and adjust a drone.

5G is a means of providing streaming evaluated as a few hundred megabits per second to gigabits per second and may complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such fast speed is needed to deliver TV in resolution of 4K or more (6K, 8K, and more), as well as virtual reality and augmented reality. Virtual reality (VR) and augmented reality (AR) applications include almost immersive sports games. A specific application program may require a special network configuration. For example, for VR games, gaming companies need to incorporate a core server into an edge network server of a network operator in order to minimize latency.

Automotive is expected to be a new important motivated force in 5G together with many use cases for mobile communication for vehicles. For example, entertainment for passengers requires high simultaneous capacity and mobile broadband with high mobility. This is because future users continue to expect connection of high quality regardless of their locations and speeds. Another use case of an automotive field is an AR dashboard. The AR dashboard causes a driver to identify an object in the dark in addition to an object seen from a front window and displays a distance from the object and a movement of the object by overlapping information talking to the driver. In the future, a wireless module enables communication between vehicles, information exchange between a vehicle and supporting infrastructure, and information exchange between a vehicle and other connected devices (e.g., devices accompanied by a pedestrian). A safety system guides alternative courses of a behavior so that a driver may drive more safely drive, thereby lowering the danger of an accident. The next stage will be a remotely controlled or self-driven vehicle. This requires very high reliability and very fast communication between different self-driven vehicles and between a vehicle and infrastructure. In the future, a self-driven vehicle will perform all driving activities and a driver will focus only upon abnormal traffic that the vehicle cannot identify. Technical requirements of a self-driven vehicle demand ultra-low latency and ultra-high reliability so that traffic safety is increased to a level that cannot be achieved by human being.

A smart city and a smart home/building mentioned as a smart society will be embedded in a high-density wireless sensor network. A distributed network of an intelligent sensor will identify conditions for costs and energy-efficient maintenance of a city or a home. Similar configurations may be performed for respective households. All of temperature sensors, window and heating controllers, burglar alarms, and home appliances are wirelessly connected. Many of these sensors are typically low in data transmission rate, power, and cost. However, real-time HD video may be demanded by a specific type of device to perform monitoring.

Consumption and distribution of energy including heat or gas is distributed at a higher level so that automated control of the distribution sensor network is demanded. The smart grid collects information and connects the sensors to each other using digital information and communication technology so as to act according to the collected information. Since this information may include behaviors of a supply company and a consumer, the smart grid may improve distribution of fuels such as electricity by a method having efficiency, reliability, economic feasibility, production sustainability, and automation. The smart grid may also be regarded as another sensor network having low latency.

Mission critical application (e.g., e-health) is one of 5G use scenarios. A health part contains many application programs capable of enjoying benefit of mobile communication. A communication system may support remote treatment that provides clinical treatment in a faraway place. Remote treatment may aid in reducing a barrier against distance and improve access to medical services that cannot be continuously available in a faraway rural area. Remote treatment is also used to perform important treatment and save lives in an emergency situation. The wireless sensor network based on mobile communication may provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

Wireless and mobile communication gradually becomes important in the field of an industrial application. Wiring is high in installation and maintenance cost. Therefore, a possibility of replacing a cable with reconstructible wireless links is an attractive opportunity in many industrial fields. However, in order to achieve this replacement, it is necessary for wireless connection to be established with latency, reliability, and capacity similar to those of the cable and management of wireless connection needs to be simplified. Low latency and a very low error probability are new requirements when connection to 5G is needed.

Logistics and freight tracking are important use cases for mobile communication that enables inventory and package tracking anywhere using a location-based information system. The use cases of logistics and freight typically demand low data rate but require location information with a wide range and reliability.

Referring to FIG. 1, the communication system 1 includes wireless devices 100 a to 100 f, base stations (BSs) 200, and a network 300. Although FIG. 1 illustrates a 5G network as an example of the network of the communication system 1, the implementations of the present disclosure are not limited to the 5G system, and can be applied to the future communication system beyond the 5G system.

The BSs 200 and the network 300 may be implemented as wireless devices and a specific wireless device may operate as a BS/network node with respect to other wireless devices.

The wireless devices 100 a to 100 f represent devices performing communication using radio access technology (RAT) (e.g., 5G new RAT (NR)) or LTE) and may be referred to as communication/radio/5G devices. The wireless devices 100 a to 100 f may include, without being limited to, a robot 100 a, vehicles 100 b-1 and 100 b-2, an extended reality (XR) device 100 c, a hand-held device 100 d, a home appliance 100 e, an IoT device 100 f, and an artificial intelligence (AI) device/server 400. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. The vehicles may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an AR/VR/Mixed Reality (MR) device and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). The home appliance may include a TV, a refrigerator, and a washing machine. The IoT device may include a sensor and a smartmeter.

In the present disclosure, the wireless devices 100 a to 100 f may be called user equipments (UEs). A UE may include, for example, a cellular phone, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate personal computer (PC), a tablet PC, an ultrabook, a vehicle, a vehicle having an autonomous traveling function, a connected car, an UAV, an AI module, a robot, an AR device, a VR device, an MR device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a FinTech device (or a financial device), a security device, a weather/environment device, a device related to a 5G service, or a device related to a fourth industrial revolution field.

The UAV may be, for example, an aircraft aviated by a wireless control signal without a human being onboard.

The VR device may include, for example, a device for implementing an object or a background of the virtual world. The AR device may include, for example, a device implemented by connecting an object or a background of the virtual world to an object or a background of the real world. The MR device may include, for example, a device implemented by merging an object or a background of the virtual world into an object or a background of the real world. The hologram device may include, for example, a device for implementing a stereoscopic image of 360 degrees by recording and reproducing stereoscopic information, using an interference phenomenon of light generated when two laser lights called holography meet.

The public safety device may include, for example, an image relay device or an image device that is wearable on the body of a user.

The MTC device and the IoT device may be, for example, devices that do not require direct human intervention or manipulation. For example, the MTC device and the IoT device may include smartmeters, vending machines, thermometers, smartbulbs, door locks, or various sensors.

The medical device may be, for example, a device used for the purpose of diagnosing, treating, relieving, curing, or preventing disease. For example, the medical device may be a device used for the purpose of diagnosing, treating, relieving, or correcting injury or impairment. For example, the medical device may be a device used for the purpose of inspecting, replacing, or modifying a structure or a function. For example, the medical device may be a device used for the purpose of adjusting pregnancy. For example, the medical device may include a device for treatment, a device for operation, a device for (in vitro) diagnosis, a hearing aid, or a device for procedure.

The security device may be, for example, a device installed to prevent a danger that may arise and to maintain safety. For example, the security device may be a camera, a closed-circuit TV (CCTV), a recorder, or a black box.

The FinTech device may be, for example, a device capable of providing a financial service such as mobile payment. For example, the FinTech device may include a payment device or a point of sales (POS) system.

The weather/environment device may include, for example, a device for monitoring or predicting a weather/environment.

The wireless devices 100 a to 100 f may be connected to the network 300 via the BSs 200. An AI technology may be applied to the wireless devices 100 a to 100 f and the wireless devices 100 a to 100 f may be connected to the AI server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, and a beyond-5G network. Although the wireless devices 100 a to 100 f may communicate with each other through the BSs 200/network 300, the wireless devices 100 a to 100 f may perform direct communication (e.g., sidelink communication) with each other without passing through the BSs 200/network 300. For example, the vehicles 100 b-1 and 100 b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V)/vehicle-to-everything (V2X) communication). The IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b and 150 c may be established between the wireless devices 100 a to 100 f and/or between wireless device 100 a to 100 f and BS 200 and/or between BSs 200. Herein, the wireless communication/connections may be established through various RATs (e.g., 5G NR) such as uplink/downlink communication 150 a, sidelink communication (or device-to-device (D2D) communication) 150 b, inter-base station communication 150 c (e.g., relay, integrated access and backhaul (JAB)), etc. The wireless devices 100 a to 100 f and the BSs 200/the wireless devices 100 a to 100 f may transmit/receive radio signals to/from each other through the wireless communication/connections 150 a, 150 b and 150 c. For example, the wireless communication/connections 150 a, 150 b and 150 c may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/de-mapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.

FIG. 2 shows an example of wireless devices to which implementations of the present disclosure is applied.

Referring to FIG. 2, a first wireless device 100 and a second wireless device 200 may transmit/receive radio signals to/from an external device through a variety of RATs (e.g., LTE and NR). In FIG. 2, {the first wireless device 100 and the second wireless device 200} may correspond to at least one of {the wireless device 100 a to 100 f and the BS 200}, {the wireless device 100 a to 100 f and the wireless device 100 a to 100 f} and/or {the BS 200 and the BS 200} of FIG. 1.

The first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally further include one or more transceivers 106 and/or one or more antennas 108. The processor(s) 102 may control the memory(s) 104 and/or the transceiver(s) 106 and may be configured to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. For example, the processor(s) 102 may process information within the memory(s) 104 to generate first information/signals and then transmit radio signals including the first information/signals through the transceiver(s) 106. The processor(s) 102 may receive radio signals including second information/signals through the transceiver(s) 106 and then store information obtained by processing the second information/signals in the memory(s) 104. The memory(s) 104 may be connected to the processor(s) 102 and may store a variety of information related to operations of the processor(s) 102. For example, the memory(s) 104 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 102 or for performing the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. Herein, the processor(s) 102 and the memory(s) 104 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 106 may be connected to the processor(s) 102 and transmit and/or receive radio signals through one or more antennas 108. Each of the transceiver(s) 106 may include a transmitter and/or a receiver. The transceiver(s) 106 may be interchangeably used with radio frequency (RF) unit(s). In the present disclosure, the first wireless device 100 may represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally further include one or more transceivers 206 and/or one or more antennas 208. The processor(s) 202 may control the memory(s) 204 and/or the transceiver(s) 206 and may be configured to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. For example, the processor(s) 202 may process information within the memory(s) 204 to generate third information/signals and then transmit radio signals including the third information/signals through the transceiver(s) 206. The processor(s) 202 may receive radio signals including fourth information/signals through the transceiver(s) 106 and then store information obtained by processing the fourth information/signals in the memory(s) 204. The memory(s) 204 may be connected to the processor(s) 202 and may store a variety of information related to operations of the processor(s) 202. For example, the memory(s) 204 may store software code including commands for performing a part or the entirety of processes controlled by the processor(s) 202 or for performing the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts described in the present disclosure. Herein, the processor(s) 202 and the memory(s) 204 may be a part of a communication modem/circuit/chip designed to implement RAT (e.g., LTE or NR). The transceiver(s) 206 may be connected to the processor(s) 202 and transmit and/or receive radio signals through one or more antennas 208. Each of the transceiver(s) 206 may include a transmitter and/or a receiver. The transceiver(s) 206 may be interchangeably used with RF unit(s). In the present disclosure, the second wireless device 200 may represent a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 will be described more specifically. One or more protocol layers may be implemented by, without being limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY) layer, media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, radio resource control (RRC) layer, and service data adaptation protocol (SDAP) layer). The one or more processors 102 and 202 may generate one or more protocol data units (PDUs) and/or one or more service data unit (SDUs) according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure and provide the generated signals to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive the signals (e.g., baseband signals) from the one or more transceivers 106 and 206 and acquire the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure.

The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors 102 and 202. descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software and the firmware or software may be configured to include the modules, procedures, or functions. Firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be included in the one or more processors 102 and 202 or stored in the one or more memories 104 and 204 so as to be driven by the one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands. The one or more memories 104 and 204 may be configured by read-only memories (ROMs), random access memories (RAMs), electrically erasable programmable read-only memories (EPROMs), flash memories, hard drives, registers, cash memories, computer-readable storage media, and/or combinations thereof. The one or more memories 104 and 204 may be located at the interior and/or exterior of the one or more processors 102 and 202. The one or more memories 104 and 204 may be connected to the one or more processors 102 and 202 through various technologies such as wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, to one or more other devices. The one or more transceivers 106 and 206 may receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, from one or more other devices. For example, the one or more transceivers 106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control so that the one or more transceivers 106 and 206 may receive user data, control information, or radio signals from one or more other devices.

The one or more transceivers 106 and 206 may be connected to the one or more antennas 108 and 208 and the one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and/or radio signals/channels, mentioned in the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure, through the one or more antennas 108 and 208. In the present disclosure, the one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports).

The one or more transceivers 106 and 206 may convert received radio signals/channels, etc., from RF band signals into baseband signals in order to process received user data, control information, radio signals/channels, etc., using the one or more processors 102 and 202. The one or more transceivers 106 and 206 may convert the user data, control information, radio signals/channels, etc., processed using the one or more processors 102 and 202 from the base band signals into the RF band signals. To this end, the one or more transceivers 106 and 206 may include (analog) oscillators and/or filters. For example, the transceivers 106 and 206 can up-convert OFDM baseband signals to a carrier frequency by their (analog) oscillators and/or filters under the control of the processors 102 and 202 and transmit the up-converted OFDM signals at the carrier frequency. The transceivers 106 and 206 may receive OFDM signals at a carrier frequency and down-convert the OFDM signals into OFDM baseband signals by their (analog) oscillators and/or filters under the control of the transceivers 102 and 202.

In the implementations of the present disclosure, a UE may operate as a transmitting device in uplink (UL) and as a receiving device in downlink (DL). In the implementations of the present disclosure, a BS may operate as a receiving device in UL and as a transmitting device in DL. Hereinafter, for convenience of description, it is mainly assumed that the first wireless device 100 acts as the UE, and the second wireless device 200 acts as the BS. For example, the processor(s) 102 connected to, mounted on or launched in the first wireless device 100 may be configured to perform the UE behavior according to an implementation of the present disclosure or control the transceiver(s) 106 to perform the UE behavior according to an implementation of the present disclosure. The processor(s) 202 connected to, mounted on or launched in the second wireless device 200 may be configured to perform the BS behavior according to an implementation of the present disclosure or control the transceiver(s) 206 to perform the BS behavior according to an implementation of the present disclosure.

In the present disclosure, a BS is also referred to as a node B (NB), an eNode B (eNB), or a gNB.

FIG. 3 shows an example of a wireless device to which implementations of the present disclosure is applied.

The wireless device may be implemented in various forms according to a use-case/service (refer to FIG. 1).

Referring to FIG. 3, wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 2 and may be configured by various elements, components, units/portions, and/or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit 110 may include a communication circuit 112 and transceiver(s) 114. For example, the communication circuit 112 may include the one or more processors 102 and 202 of FIG. 2 and/or the one or more memories 104 and 204 of FIG. 2. For example, the transceiver(s) 114 may include the one or more transceivers 106 and 206 of FIG. 2 and/or the one or more antennas 108 and 208 of FIG. 2. The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls overall operation of each of the wireless devices 100 and 200. For example, the control unit 120 may control an electric/mechanical operation of each of the wireless devices 100 and 200 based on programs/code/commands/information stored in the memory unit 130. The control unit 120 may transmit the information stored in the memory unit 130 to the exterior (e.g., other communication devices) via the communication unit 110 through a wireless/wired interface or store, in the memory unit 130, information received through the wireless/wired interface from the exterior (e.g., other communication devices) via the communication unit 110.

The additional components 140 may be variously configured according to types of the wireless devices 100 and 200. For example, the additional components 140 may include at least one of a power unit/battery, input/output (I/O) unit (e.g., audio I/O port, video I/O port), a driving unit, and a computing unit. The wireless devices 100 and 200 may be implemented in the form of, without being limited to, the robot (100 a of FIG. 1), the vehicles (100 b-1 and 100 b-2 of FIG. 1), the XR device (100 c of FIG. 1), the hand-held device (100 d of FIG. 1), the home appliance (100 e of FIG. 1), the IoT device (100 f of FIG. 1), a digital broadcast terminal, a hologram device, a public safety device, an MTC device, a medicine device, a FinTech device (or a finance device), a security device, a climate/environment device, the AI server/device (400 of FIG. 1), the BSs (200 of FIG. 1), a network node, etc. The wireless devices 100 and 200 may be used in a mobile or fixed place according to a use-example/service.

In FIG. 3, the entirety of the various elements, components, units/portions, and/or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected by wire and the control unit 120 and first units (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit/portion, and/or module within the wireless devices 100 and 200 may further include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor (AP), an electronic control unit (ECU), a graphical processing unit, and a memory control processor. As another example, the memory 130 may be configured by a RAM, a DRAM, a ROM, a flash memory, a volatile memory, a non-volatile memory, and/or a combination thereof.

FIG. 4 shows another example of wireless devices to which implementations of the present disclosure is applied.

Referring to FIG. 4, wireless devices 100 and 200 may correspond to the wireless devices 100 and 200 of FIG. 2 and may be configured by various elements, components, units/portions, and/or modules.

The first wireless device 100 may include at least one transceiver, such as a transceiver 106, and at least one processing chip, such as a processing chip 101. The processing chip 101 may include at least one processor, such a processor 102, and at least one memory, such as a memory 104. The memory 104 may be operably connectable to the processor 102. The memory 104 may store various types of information and/or instructions. The memory 104 may store a software code 105 which implements instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may implement instructions that, when executed by the processor 102, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 105 may control the processor 102 to perform one or more protocols. For example, the software code 105 may control the processor 102 may perform one or more layers of the radio interface protocol.

The second wireless device 200 may include at least one transceiver, such as a transceiver 206, and at least one processing chip, such as a processing chip 201. The processing chip 201 may include at least one processor, such a processor 202, and at least one memory, such as a memory 204. The memory 204 may be operably connectable to the processor 202. The memory 204 may store various types of information and/or instructions. The memory 204 may store a software code 205 which implements instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may implement instructions that, when executed by the processor 202, perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. For example, the software code 205 may control the processor 202 to perform one or more protocols. For example, the software code 205 may control the processor 202 may perform one or more layers of the radio interface protocol.

FIG. 5 shows an example of UE to which implementations of the present disclosure is applied.

Referring to FIG. 5, a UE 100 may correspond to the first wireless device 100 of FIG. 2 and/or the first wireless device 100 of FIG. 4.

A UE 100 includes a processor 102, a memory 104, a transceiver 106, one or more antennas 108, a power management module 110, a battery 1112, a display 114, a keypad 116, a subscriber identification module (SIM) card 118, a speaker 120, and a microphone 122.

The processor 102 may be configured to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The processor 102 may be configured to control one or more other components of the UE 100 to implement the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. Layers of the radio interface protocol may be implemented in the processor 102. The processor 102 may include ASIC, other chipset, logic circuit and/or data processing device. The processor 102 may be an application processor. The processor 102 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), a modem (modulator and demodulator). An example of the processor 102 may be found in SNAPDRAGON™ series of processors made by Qualcomm®, EXYNOS™ series of processors made by Samsung®, A series of processors made by Apple, HELIO™ series of processors made by MediaTek®, ATOM™ series of processors made by Intel® or a corresponding next generation processor.

The memory 104 is operatively coupled with the processor 102 and stores a variety of information to operate the processor 102. The memory 104 may include ROM, RAM, flash memory, memory card, storage medium and/or other storage device. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, etc.) that perform the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in the present disclosure. The modules can be stored in the memory 104 and executed by the processor 102. The memory 104 can be implemented within the processor 102 or external to the processor 102 in which case those can be communicatively coupled to the processor 102 via various means as is known in the art.

The transceiver 106 is operatively coupled with the processor 102, and transmits and/or receives a radio signal. The transceiver 106 includes a transmitter and a receiver. The transceiver 106 may include baseband circuitry to process radio frequency signals. The transceiver 106 controls the one or more antennas 108 to transmit and/or receive a radio signal.

The power management module 110 manages power for the processor 102 and/or the transceiver 106. The battery 112 supplies power to the power management module 110.

The display 114 outputs results processed by the processor 102. The keypad 116 receives inputs to be used by the processor 102. The keypad 16 may be shown on the display 114.

The SIM card 118 is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). It is also possible to store contact information on many SIM cards.

The speaker 120 outputs sound-related results processed by the processor 102. The microphone 122 receives sound-related inputs to be used by the processor 102.

FIGS. 6 and 7 show an example of protocol stacks in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

In particular, FIG. 6 illustrates an example of a radio interface user plane protocol stack between a UE and a BS and FIG. 7 illustrates an example of a radio interface control plane protocol stack between a UE and a BS. The control plane refers to a path through which control messages used to manage call by a UE and a network are transported. The user plane refers to a path through which data generated in an application layer, for example, voice data or Internet packet data are transported. Referring to FIG. 6, the user plane protocol stack may be divided into Layer 1 (i.e., a PHY layer) and Layer 2. Referring to FIG. 7, the control plane protocol stack may be divided into Layer 1 (i.e., a PHY layer), Layer 2, Layer 3 (e.g., an RRC layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 and Layer 3 are referred to as an access stratum (AS).

In the 3GPP LTE system, the Layer 2 is split into the following sublayers: MAC, RLC, and PDCP. In the 3GPP NR system, the Layer 2 is split into the following sublayers: MAC, RLC, PDCP and SDAP. The PHY layer offers to the MAC sublayer transport channels, the MAC sublayer offers to the RLC sublayer logical channels, the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCP sublayer offers to the SDAP sublayer radio bearers. The SDAP sublayer offers to 5G core network quality of service (QoS) flows.

In the 3GPP NR system, the main services and functions of the MAC sublayer include: mapping between logical channels and transport channels; multiplexing/de-multiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels; scheduling information reporting; error correction through hybrid automatic repeat request (HARQ) (one HARQ entity per cell in case of carrier aggregation (CA)); priority handling between UEs by means of dynamic scheduling; priority handling between logical channels of one UE by means of logical channel prioritization; padding. A single MAC entity may support multiple numerologies, transmission timings and cells. Mapping restrictions in logical channel prioritization control which numerology(ies), cell(s), and transmission timing(s) a logical channel can use.

Different kinds of data transfer services are offered by MAC. To accommodate different kinds of data transfer services, multiple types of logical channels are defined, i.e., each supporting transfer of a particular type of information. Each logical channel type is defined by what type of information is transferred. Logical channels are classified into two groups: control channels and traffic channels. Control channels are used for the transfer of control plane information only, and traffic channels are used for the transfer of user plane information only. Broadcast control channel (BCCH) is a downlink logical channel for broadcasting system control information, paging control channel (PCCH) is a downlink logical channel that transfers paging information, system information change notifications and indications of ongoing public warning service (PWS) broadcasts, common control channel (CCCH) is a logical channel for transmitting control information between UEs and network and used for UEs having no RRC connection with the network, and dedicated control channel (DCCH) is a point-to-point bi-directional logical channel that transmits dedicated control information between a UE and the network and used by UEs having an RRC connection. Dedicated traffic channel (DTCH) is a point-to-point logical channel, dedicated to one UE, for the transfer of user information. A DTCH can exist in both uplink and downlink. In downlink, the following connections between logical channels and transport channels exist: BCCH can be mapped to broadcast channel (BCH); BCCH can be mapped to downlink shared channel (DL-SCH); PCCH can be mapped to paging channel (PCH); CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mapped to DL-SCH. In uplink, the following connections between logical channels and transport channels exist: CCCH can be mapped to uplink shared channel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mapped to UL-SCH.

The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged node (AM). The RLC configuration is per logical channel with no dependency on numerologies and/or transmission durations. In the 3GPP NR system, the main services and functions of the RLC sublayer depend on the transmission mode and include: transfer of upper layer PDUs; sequence numbering independent of the one in PDCP (UM and AM); error correction through ARQ (AM only); segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs; reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDU discard (AM and UM); RLC re-establishment; protocol error detection (AM only).

In the 3GPP NR system, the main services and functions of the PDCP sublayer for the user plane include: sequence numbering; header compression and decompression using robust header compression (ROHC); transfer of user data; reordering and duplicate detection; in-order delivery; PDCP PDU routing (in case of split bearers); retransmission of PDCP SDUs; ciphering, deciphering and integrity protection; PDCP SDU discard; PDCP re-establishment and data recovery for RLC AM; PDCP status reporting for RLC AM; duplication of PDCP PDUs and duplicate discard indication to lower layers. The main services and functions of the PDCP sublayer for the control plane include: sequence numbering; ciphering, deciphering and integrity protection; transfer of control plane data; reordering and duplicate detection; in-order delivery; duplication of PDCP PDUs and duplicate discard indication to lower layers.

In the 3GPP NR system, the main services and functions of SDAP include: mapping between a QoS flow and a data radio bearer; marking QoS flow ID (QFI) in both DL and UL packets. A single protocol entity of SDAP is configured for each individual PDU session.

In the 3GPP NR system, the main services and functions of the RRC sublayer include: broadcast of system information related to AS and NAS; paging initiated by 5GC or NG-RAN; establishment, maintenance and release of an RRC connection between the UE and NG-RAN; security functions including key management; establishment, configuration, maintenance and release of signaling radio bearers (SRBs) and data radio bearers (DRBs); mobility functions (including: handover and context transfer, UE cell selection and reselection and control of cell selection and reselection, inter-RAT mobility); QoS management functions; UE measurement reporting and control of the reporting; detection of and recovery from radio link failure; NAS message transfer to/from NAS from/to UE.

FIG. 8 shows a frame structure in a 3GPP based wireless communication system to which implementations of the present disclosure is applied.

The frame structure shown in FIG. 8 is purely exemplary and the number of subframes, the number of slots, and/or the number of symbols in a frame may be variously changed. In the 3GPP based wireless communication system, OFDM numerologies (e.g., subcarrier spacing (SCS), transmission time interval (TTI) duration) may be differently configured between a plurality of cells aggregated for one UE. For example, if a UE is configured with different SCSs for cells aggregated for the cell, an (absolute time) duration of a time resource (e.g., a subframe, a slot, or a TTI) including the same number of symbols may be different among the aggregated cells. Herein, symbols may include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbols).

Referring to FIG. 8, downlink and uplink transmissions are organized into frames. Each frame has T_(f)=10 ms duration. Each frame is divided into two half-frames, where each of the half-frames has 5 ms duration. Each half-frame consists of 5 subframes, where the duration T_(sf) per subframe is 1 ms. Each subframe is divided into slots and the number of slots in a subframe depends on a subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP, each slot includes 14 OFDM symbols and, in an extended CP, each slot includes 12 OFDM symbols. The numerology is based on exponentially scalable subcarrier spacing Δf=2^(u)*15 kHz.

Table 1 shows the number of OFDM symbols per slot N^(slot) _(symb), the number of slots per frame N^(frame,u) _(slot), and the number of slots per subframe N^(subframe,u) _(slot) for the normal CP, according to the subcarrier spacing Δf=2^(u)*15 kHz.

TABLE 1 u N^(slot) _(symb) N^(frame,u) _(slot) N^(subframe,u) _(slot) 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

Table 2 shows the number of OFDM symbols per slot N^(slot) _(symb), the number of slots per frame N^(frame,u) _(slot), and the number of slots per subframe N^(subframe,u) _(slot) for the extended CP, according to the subcarrier spacing Δf=2^(u)*15 kHz.

TABLE 2 u N^(slot) _(symb) N^(frame,u) _(slot) N^(subframe,u) _(slot) 2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the time domain. For each numerology (e.g., subcarrier spacing) and carrier, a resource grid of N^(size,u) _(grid,x)*N^(RB) _(sc) subcarriers and N^(subframe,u) _(symb) OFDM symbols is defined, starting at common resource block (CRB) N^(start,u) _(grid) indicated by higher-layer signaling (e.g., RRC signaling), where N^(size,u) _(grid,x) is the number of resource blocks (RBs) in the resource grid and the subscript x is DL for downlink and UL for uplink. N^(RB) _(sc) is the number of subcarriers per RB. In the 3GPP based wireless communication system, N^(RB) _(sc) is 12 generally. There is one resource grid for a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL). The carrier bandwidth N^(size,u) _(grid) for subcarrier spacing configuration u is given by the higher-layer parameter (e.g., RRC parameter). Each element in the resource grid for the antenna port p and the subcarrier spacing configuration u is referred to as a resource element (RE) and one complex symbol may be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l representing a symbol location relative to a reference point in the time domain. In the 3GPP based wireless communication system, an RB is defined by 12 consecutive subcarriers in the frequency domain.

In the 3GPP NR system, RBs are classified into CRBs and physical resource blocks (PRBs). CRBs are numbered from 0 and upwards in the frequency domain for subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for subcarrier spacing configuration u coincides with ‘point A’ which serves as a common reference point for resource block grids. In the 3GPP NR system, PRBs are defined within a bandwidth part (BWP) and numbered from 0 to N^(size) _(BWP,i)−1, where i is the number of the bandwidth part. The relation between the physical resource block n_(PRB) in the bandwidth part i and the common resource block n_(CRB) is as follows: n_(PRB)=n_(CRB)+N^(size) _(BWP,i) where N^(size) _(BWP,i) is the common resource block where bandwidth part starts relative to CRB 0. The BWP includes a plurality of consecutive RBs. A carrier may include a maximum of N (e.g., 5) BWPs. A UE may be configured with one or more BWPs on a given component carrier. Only one BWP among BWPs configured to the UE can active at a time. The active BWP defines the UE's operating bandwidth within the cell's operating bandwidth.

The NR frequency band may be defined as two types of frequency range, i.e., FR1 and FR2. The numerical value of the frequency range may be changed. For example, the frequency ranges of the two types (FR1 and FR2) may be as shown in Table 3 below. For ease of explanation, in the frequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”, FR2 may mean “above 6 GHz range,” and may be referred to as millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier designation frequency range Spacing FR1  450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NR system may be changed. For example, FR1 may include a frequency band of 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more included in FR1 may include an unlicensed band. Unlicensed bands may be used for a variety of purposes, for example for communication for vehicles (e.g., autonomous driving).

TABLE 4 Frequency Range Corresponding Subcarrier designation frequency range Spacing FR1  410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

In the present disclosure, the term “cell” may refer to a geographic area to which one or more nodes provide a communication system, or refer to radio resources. A “cell” as a geographic area may be understood as coverage within which a node can provide service using a carrier and a “cell” as radio resources (e.g., time-frequency resources) is associated with bandwidth which is a frequency range configured by the carrier. The “cell” associated with the radio resources is defined by a combination of downlink resources and uplink resources, for example, a combination of a DL component carrier (CC) and a UL CC. The cell may be configured by downlink resources only, or may be configured by downlink resources and uplink resources. Since DL coverage, which is a range within which the node is capable of transmitting a valid signal, and UL coverage, which is a range within which the node is capable of receiving the valid signal from the UE, depends upon a carrier carrying the signal, the coverage of the node may be associated with coverage of the “cell” of radio resources used by the node. Accordingly, the term “cell” may be used to represent service coverage of the node sometimes, radio resources at other times, or a range that signals using the radio resources can reach with valid strength at other times.

In CA, two or more CCs are aggregated. A UE may simultaneously receive or transmit on one or multiple CCs depending on its capabilities. CA is supported for both contiguous and non-contiguous CCs. When CA is configured, the UE only has one RRC connection with the network. At RRC connection establishment/re-establishment/handover, one serving cell provides the NAS mobility information, and at RRC connection re-establishment/handover, one serving cell provides the security input. This cell is referred to as the primary cell (PCell). The PCell is a cell, operating on the primary frequency, in which the UE either performs the initial connection establishment procedure or initiates the connection re-establishment procedure. Depending on UE capabilities, secondary cells (SCells) can be configured to form together with the PCell a set of serving cells. An SCell is a cell providing additional radio resources on top of special cell (SpCell). The configured set of serving cells for a UE therefore always consists of one PCell and one or more SCells. For dual connectivity (DC) operation, the term SpCell refers to the PCell of the master cell group (MCG) or the primary SCell (PSCell) of the secondary cell group (SCG). An SpCell supports PUCCH transmission and contention-based random access, and is always activated. The MCG is a group of serving cells associated with a master node, comprised of the SpCell (PCell) and optionally one or more SCells. The SCG is the subset of serving cells associated with a secondary node, comprised of the PSCell and zero or more SCells, for a UE configured with DC. For a UE in RRC_CONNECTED not configured with CA/DC, there is only one serving cell comprised of the PCell. For a UE in RRC_CONNECTED configured with CA/DC, the term “serving cells” is used to denote the set of cells comprised of the SpCell(s) and all SCells. In DC, two MAC entities are configured in a UE: one for the MCG and one for the SCG.

FIG. 9 shows a data flow example in the 3GPP NR system to which implementations of the present disclosure is applied.

Referring to FIG. 9, “RB” denotes a radio bearer, and “H” denotes a header. Radio bearers are categorized into two groups: DRBs for user plane data and SRBs for control plane data. The MAC PDU is transmitted/received using radio resources through the PHY layer to/from an external device. The MAC PDU arrives to the PHY layer in the form of a transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH are mapped to their physical channels physical uplink shared channel (PUSCH) and physical random access channel (PRACH), respectively, and the downlink transport channels DL-SCH, BCH and PCH are mapped to physical downlink shared channel (PDSCH), physical broadcast channel (PBCH) and PDSCH, respectively. In the PHY layer, uplink control information (UCI) is mapped to physical uplink control channel (PUCCH), and downlink control information (DCI) is mapped to physical downlink control channel (PDCCH). A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCH is transmitted by a BS via a PDSCH based on a DL assignment.

In order to transmit data unit(s) of the present disclosure on UL-SCH, a UE shall have uplink resources available to the UE. In order to receive data unit(s) of the present disclosure on DL-SCH, a UE shall have downlink resources available to the UE. The resource allocation includes time domain resource allocation and frequency domain resource allocation. In the present disclosure, uplink resource allocation is also referred to as uplink grant, and downlink resource allocation is also referred to as downlink assignment. An uplink grant is either received by the UE dynamically on PDCCH, in a random access response, or configured to the UE semi-persistently by RRC. Downlink assignment is either received by the UE dynamically on the PDCCH, or configured to the UE semi-persistently by RRC signaling from the BS.

In UL, the BS can dynamically allocate resources to UEs via the cell radio network temporary identifier (C-RNTI) on PDCCH(s). A UE always monitors the PDCCH(s) in order to find possible grants for uplink transmission when its downlink reception is enabled (activity governed by discontinuous reception (DRX) when configured). In addition, with configured grants, the BS can allocate uplink resources for the initial HARQ transmissions to UEs. Two types of configured uplink grants are defined: Type 1 and Type 2. With Type 1, RRC directly provides the configured uplink grant (including the periodicity). With Type 2, RRC defines the periodicity of the configured uplink grant while PDCCH addressed to configured scheduling RNTI (CS-RNTI) can either signal and activate the configured uplink grant, or deactivate it. That is, a PDCCH addressed to CS-RNTI indicates that the uplink grant can be implicitly reused according to the periodicity defined by RRC, until deactivated.

In DL, the BS can dynamically allocate resources to UEs via the C-RNTI on PDCCH(s). A UE always monitors the PDCCH(s) in order to find possible assignments when its downlink reception is enabled (activity governed by DRX when configured). In addition, with semi-persistent Scheduling (SPS), the BS can allocate downlink resources for the initial HARQ transmissions to UEs. RRC defines the periodicity of the configured downlink assignments while PDCCH addressed to CS-RNTI can either signal and activate the configured downlink assignment, or deactivate it. In other words, a PDCCH addressed to CS-RNTI indicates that the downlink assignment can be implicitly reused according to the periodicity defined by RRC, until deactivated.

For resource allocation by PDCCH (i.e., resource allocation by DCI), PDCCH can be used to schedule DL transmissions on PDSCH and UL transmissions on PUSCH, where the DCI on PDCCH includes: downlink assignments containing at least modulation and coding format (e.g., modulation and coding scheme (MCS) index I_(MCS)), resource allocation, and hybrid-ARQ information related to DL-SCH; or uplink scheduling grants containing at least modulation and coding format, resource allocation, and hybrid-ARQ information related to UL-SCH. The size and usage of the DCI carried by one PDCCH are varied depending on DCI formats. For example, in the 3GPP NR system, DCI format 0_0 or DCI format 0_1 is used for scheduling of PUSCH in one cell, and DCI format 1_0 or DCI format 1_1 is used for scheduling of PDSCH in one cell.

FIG. 10 shows an example of PDSCH time domain resource allocation by PDCCH to which implementations of the present disclosure is applied. FIG. 11 shows an example of PUSCH time resource allocation by PDCCH to which implementations of the present disclosure is applied.

DCI carried by a PDCCH for scheduling PDSCH or PUSCH includes a value m for a row index m+1 to an allocation table for PDSCH or PUSCH. Either a predefined default PDSCH time domain allocation A, B or C is applied as the allocation table for PDSCH, or RRC configured pdsch-TimeDomainAllocationList is applied as the allocation table for PDSCH. Either a predefined default PUSCH time domain allocation A is applied as the allocation table for PUSCH, or the RRC configured pusch-TimeDomainAllocationList is applied as the allocation table for PUSCH. Which PDSCH time domain resource allocation configuration to apply and which PUSCH time domain resource allocation table to apply are determined according to a fixed/predefined rule.

Each indexed row in PDSCH time domain allocation configurations defines the slot offset K₀, the start and length indicator SLIV, or directly the start symbol S and the allocation length L, and the PDSCH mapping type to be assumed in the PDSCH reception. Each indexed row in PUSCH time domain allocation configurations defines the slot offset K₂, the start and length indicator SLIV, or directly the start symbol S and the allocation length L, and the PUSCH mapping type to be assumed in the PUSCH reception. K₀ for PDSCH, or K₂ for PUSCH is the timing difference between a slot with a PDCCH and a slot with PDSCH or PUSCH corresponding to the PDCCH. SLIV is a joint indication of starting symbol S relative to the start of the slot with PDSCH or PUSCH, and the number L of consecutive symbols counting from the symbol S. For PDSCH/PUSCH mapping type, there are two mapping types: one is Mapping Type A where demodulation reference signal (DMRS) is positioned in 3^(rd) or 4^(th) symbol of a slot depending on the RRC signaling, and other one is Mapping Type B where DMRS is positioned in the first allocated symbol.

The scheduling DCI includes the Frequency domain resource assignment field which provides assignment information on resource blocks used for PDSCH or PUSCH. For example, the Frequency domain resource assignment field may provide a UE with information on a cell for PDSCH or PUSCH transmission, information on a bandwidth part for PDSCH or PUSCH transmission, information on resource blocks for PDSCH or PUSCH transmission.

For resource allocation by RRC, as mentioned above, in uplink, there are two types of transmission without dynamic grant: configured grant Type 1 where an uplink grant is provided by RRC, and stored as configured grant; and configured grant Type 2 where an uplink grant is provided by PDCCH, and stored or cleared as configured uplink grant based on L1 signaling indicating configured uplink grant activation or deactivation. Type 1 and Type 2 are configured by RRC per serving cell and per BWP. Multiple configurations can be active simultaneously only on different serving cells. For Type 2, activation and deactivation are independent among the serving cells. For the same serving cell, the MAC entity is configured with either Type 1 or Type 2.

A UE is provided with at least the following parameters via RRC signaling from a BS when the configured grant type 1 is configured:

-   -   cs-RNTI which is CS-RNTI for retransmission;     -   periodicity which provides periodicity of the configured grant         Type 1;     -   timeDomainOffset which represents offset of a resource with         respect to SFN=0 in time domain;     -   timeDomainAllocation value m which provides a row index m+1         pointing to an allocation table, indicating a combination of a         start symbol S and length L and PUSCH mapping type;     -   frequencyDomainAllocation which provides frequency domain         resource allocation; and     -   mcsAndTBS which provides I_(MCS) representing the modulation         order, target code rate and transport block size. Upon         configuration of a configured grant Type 1 for a serving cell by         RRC, the UE stores the uplink grant provided by RRC as a         configured uplink grant for the indicated serving cell, and         initialize or re-initialise the configured uplink grant to start         in the symbol according to timeDomainOffset and S (derived from         SLIV), and to reoccur with periodicity. After an uplink grant is         configured for a configured grant Type 1, the UE considers that         the uplink grant recurs associated with each symbol for which:         [(SFN*numberOfSlotsPerFrame (numberOfSymbolsPerSlot)+(slot         number in the frame×numberOfSymbolsPerSlot)+symbol number in the         slot]=(timeDomainOffset*numberOfSymbolsPerSlot+S+N*periodicity)         modulo (1024*numberOfSlotsPerFrame*numberOfSymbolsPerSlot), for         all N>=0.

A UE is provided with at least the following parameters via RRC signaling from a BS when the configured gran Type 2 is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and         retransmission; and     -   periodicity which provides periodicity of the configured grant         Type 2. The actual uplink grant is provided to the UE by the         PDCCH (addressed to CS-RNTI). After an uplink grant is         configured for a configured grant Type 2, the UE considers that         the uplink grant recurs associated with each symbol for which:         [(SFN*numberOfSlotsPerFrame*numberOfSymbolsPerSlot)+(slot number         in the frame*numberOfSymbolsPerSlot)+symbol number in the         slot]=[(SFN_(start time)*numberOfSlotsPerFrame*numberOfSymbolsPerSlot+slot_(start time)*numberOfSymbolsPerSlot+symbol_(stat time))+N*periodicity]         modulo (1024×numberOfSlotsPerFrame*numberOfSymbolsPerSlot), for         all N>=0, where SFN_(start time), slot_(start time), and         symbol_(stat time) are the SFN, slot, and symbol, respectively,         of the first transmission opportunity of PUSCH where the         configured uplink grant was (re-)initialised.         numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the         number of consecutive slots per frame and the number of         consecutive OFDM symbols per slot, respectively.

For downlink, a UE may be configured with SPS per serving cell and per BWP by RRC signaling from a BS. Multiple configurations can be active simultaneously only on different serving cells. Activation and deactivation of the DL SPS are independent among the serving cells. For DL SPS, a DL assignment is provided to the UE by PDCCH, and stored or cleared based on L1 signaling indicating SPS activation or deactivation. A UE is provided with the following parameters via RRC signaling from a BS when SPS is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and         retransmission;     -   nrofHARQ-Processes: which provides the number of configured HARQ         processes for SPS;     -   periodicity which provides periodicity of configured downlink         assignment for SPS. When SPS is released by upper layers, all         the corresponding configurations shall be released.

After a downlink assignment is configured for SPS, the UE considers sequentially that the N^(th) downlink assignment occurs in the slot for which: (numberOfSlotsPerFrame*SFN+slot number in the frame)=[(numberOfSlotsPerFrame*SFN_(start time)+slot_(start time))+N*periodicity*numberOfSlotsPerFrame/10] modulo (1024*numberOfSlotsPerFrame), where SFN_(start time) and slot_(start time) are the SFN and slot, respectively, of the first transmission of PDSCH where the configured downlink assignment was (re-)initialized.

A UE validates, for scheduling activation or scheduling release, a DL SPS assignment PDCCH or configured UL grant type 2 PDCCH if the cyclic redundancy check (CRC) of a corresponding DCI format is scrambled with CS-RNTI provided by the RRC parameter cs-RNTI and the new data indicator field for the enabled transport block is set to 0. Validation of the DCI format is achieved if all fields for the DCI format are set according to Table 5 or Table 6 below. Table 5 shows special fields for DL SPS and UL grant Type 2 scheduling activation PDCCH validation, and Table 6 shows special fields for DL SPS and UL grant Type 2 scheduling release PDCCH validation.

TABLE 5 DCI format DCI format DCI format 0_0/0_1 1_0 1_1 HARQ process set to all ‘0’s set to all ‘0’s set to all ‘0’s number Redundancy set to ‘00’ set to ‘00’ For the enabled version transport block: set to ‘00’

TABLE 6 DCI format DCI format 0_0 1_0 HARQ process set to all ‘0’s set to all ‘0’s number Redundancy set to ‘00’ set to ‘00’ version Modulation and set to all ‘1’s set to all ‘1’s coding scheme Resource block set to all ‘1’s set to all ‘1’s assignment

Actual DL assignment and actual UL grant, and the corresponding modulation and coding scheme are provided by the resource assignment fields (e.g., time domain resource assignment field which provides Time domain resource assignment value m, frequency domain resource assignment field which provides the frequency resource block allocation, modulation and coding scheme field) in the DCI format carried by the DL SPS and UL grant Type 2 scheduling activation PDCCH. If validation is achieved, the UE considers the information in the DCI format as valid activation or valid release of DL SPS or configured UL grant Type 2.

The data unit(s) of the present disclosure is(are) subject to the physical layer processing at a transmitting side before transmission via radio interface, and the radio signals carrying the data unit(s) of the present disclosure are subject to the physical layer processing at a receiving side.

FIG. 12 shows an example of physical layer processing at a transmitting side to which implementations of the present disclosure is applied.

The following tables show the mapping of the transport channels and control information to its corresponding physical channels. In particular, Table 7 specifies the mapping of the uplink transport channels to their corresponding physical channels, Table 8 specifies the mapping of the uplink control channel information to its corresponding physical channel, Table 9 specifies the mapping of the downlink transport channels to their corresponding physical channels, and Table 10 specifies the mapping of the downlink control channel information to its corresponding physical channel.

TABLE 7 Transport Channel Physical Channel UL-SCH PUSCH RACH PRACH

TABLE 8 Control information Physical Channel UCI PUCCH, PUSCH

TABLE 9 Transport Channel Physical Channel DL-SCH PDSCH BCH PBCH PCH PDSCH

TABLE 10 Control information Physical Channel DCI PDCCH

Each step of FIG. 12 is described below in detail.

1) Encoding

Data and control streams from/to MAC layer are encoded to offer transport and control services over the radio transmission link in the PHY layer. For example, a transport block from MAC layer is encoded into a codeword at a transmitting side. Channel coding scheme is a combination of error detection, error correcting, rate matching, interleaving and transport channel or control information mapping onto/splitting from physical channels.

In the NR LTE system, following channel coding schemes are used for the different types of transport channels and the different control information types. Table 11 specifies the mapping of transport channels to respective coding scheme. Table 12 specifies the mapping of control information to respective coding scheme.

TABLE 11 Transport Channel Coding scheme UL-SCH Low density parity check DL-SCH (LDPC) code PCH BCH Polar code

TABLE 12 Control Information Coding scheme DCI Polar code UCI Block code Polar code

For transmission of a DL transport block (i.e., a DL MAC PDU) or a UL transport block (i.e., a UL MAC PDU), a transport block CRC sequence is attached to provide error detection for a receiving side. In the 3GPP NR system, the communication device uses LDPC codes in encoding/decoding UL-SCH and DL-SCH. The 3GPP NR system supports two LDPC base graphs (i.e., two LDPC base matrixes): LDPC base graph 1 optimized for small transport blocks and LDPC base graph 2 for larger transport blocks. Either LDPC base graph 1 or 2 is selected based on the size of the transport block and coding rate R. The coding rate R is indicated by the MCS index I_(MCS). The MCS index is dynamically provided to a UE by PDCCH scheduling PUSCH or PDSCH, provided to a UE by PDCCH activating or (re-)initializing the UL configured grant 2 or DL SPS, or provided to a UE by RRC signaling related to the UL configured grant Type 1. If the CRC attached transport block is larger than the maximum code block size for the selected LDPC base graph, the CRC attached transport block may be segmented into code blocks, and an additional CRC sequence is attached to each code block. The maximum code block sizes for the LDPC base graph 1 and the LDPC base graph 2 are 8448 bits and 3480 bits, respectively. If the CRC attached transport block is not larger than the maximum code block size for the selected LDPC base graph, the CRC attached transport block is encoded with the selected LDPC base graph. Each code block of the transport block is encoded with the selected LDPC base graph. The LDPC coded blocks are then individually rat matched. Code block concatenation is performed to create a codeword for transmission on PDSCH or PUSCH. For PDSCH, up to 2 codewords (i.e., up to 2 transport blocks) can be transmitted simultaneously on the PDSCH. PUSCH can be used for transmission of UL-SCH data and layer 1/2 control information.

Although not shown in FIG. 12, the layer 1/2 control information may be multiplexed with the codeword for UL-SCH data.

2) Scrambling and Modulation

The bits of the codeword are scrambled and modulated to generate a block of complex-valued modulation symbols.

3) Layer Mapping

The complex-valued modulation symbols of the codeword are mapped to one or more multiple input multiple output (MIMO) layers. A codeword can be mapped to up to 4 layers. A PDSCH can carry two codewords, and thus a PDSCH can support up to 8-layer transmission. A PUSCH supports a single codeword, and thus a PUSCH can support up to 4-layer transmission.

4) Transform Precoding

The DL transmission waveform is conventional OFDM using a CP. For DL, transform precoding (in other words, DFT) is not applied.

The UL transmission waveform is conventional OFDM using a CP with a transform precoding function performing DFT spreading that can be disabled or enabled. In the 3GPP NR system, for UL, the transform precoding can be optionally applied if enabled. The transform precoding is to spread UL data in a special way to reduce peak-to-average power ratio (PAPR) of the waveform. The transform precoding is a form of DFT. In other words, the 3GPP NR system supports two options for UL waveform: one is CP-OFDM (same as DL waveform) and the other one is DFT-s-OFDM. Whether a UE has to use CP-OFDM or DFT-s-OFDM is determined by a BS via RRC parameters.

5) Subcarrier Mapping

The layers are mapped to antenna ports. In DL, for the layers to antenna ports mapping, a transparent manner (non-codebook based) mapping is supported and how beamforming or MIMO precoding is performed is transparent to the UE. In UL, for the layers to antenna ports mapping, both the non-codebook based mapping and a codebook based mapping are supported.

For each antenna port (i.e., layer) used for transmission of the physical channel (e.g., PDSCH, PUSCH), the complex-valued modulation symbols are mapped to subcarriers in resource blocks allocated to the physical channel.

6) OFDM Modulation

The communication device at the transmitting side generates a time-continuous OFDM baseband signal on antenna port p and subcarrier spacing configuration u for OFDM symbol l in a TTI for a physical channel by adding a CP and performing inverse fast Fourier transform (IFFT). For example, for each OFDM symbol, the communication device at the transmitting side may perform IFFT on the complex-valued modulation symbols mapped to resource blocks in the corresponding OFDM symbol and add a CP to the IFFT-ed signal to generate the OFDM baseband signal.

7) Up-Conversion

The communication device at the transmitting side up-converts the OFDM baseband signal for antenna port p, subcarrier spacing configuration u and OFDM symbol l to a carrier frequency f₀ of a cell to which the physical channel is assigned.

The processor 102, 202 in FIG. 2, the processor included in the communication unit 112 and/or the control unit 120 in FIG. 3, the processor 102, 202 in FIG. 4 and/or the processor 102 in FIG. 5 may be configured to perform encoding, schrambling, modulation, layer mapping, transform precoding (for UL), subcarrier mapping, and OFDM modulation. The processor 102, 202 in FIG. 2, the processor included in the communication unit 112 and/or the control unit 120 in FIG. 3, the processor 102, 202 in FIG. 4 and/or the processor 102 in FIG. 5 may control the transceiver 106, 206 in FIG. 2, the transceiver 114 in FIG. 3, the transceiver 106, 206 in FIG. 4 and/or the transceiver 106 in FIG. 5 to up-convert the OFDM baseband signal onto the carrier frequency to generate radio frequency (RF) signals. The radio frequency signals are transmitted through antennas to an external device.

FIG. 13 shows an example of physical layer processing at a receiving side to which implementations of the present disclosure is applied.

The physical layer processing at the receiving side is basically the inverse processing of the physical layer processing at the transmitting side. Each step of FIG. 13 is described below in detail.

1) Frequency Down-Conversion

The communication device at a receiving side receives RF signals at a carrier frequency through antennas. The transceiver 106, 206 in FIG. 2, the transceiver 114 in FIG. 3, the transceiver 106, 206 in FIG. 4 and/or the transceiver 106 in FIG. 5 receiving the RF signals at the carrier frequency down-converts the carrier frequency of the RF signals into the baseband in order to obtain OFDM baseband signals.

2) OFDM Demodulation

The communication device at the receiving side obtains complex-valued modulation symbols via CP detachment and FFT. For example, for each OFDM symbol, the communication device at the receiving side removes a CP from the OFDM baseband signals and performs FFT on the CP-removed OFDM baseband signals to obtain complex-valued modulation symbols for antenna port p, subcarrier spacing u and OFDM symbol l.

3) Subcarrier De-Mapping

The subcarrier de-mapping is performed on the complex-valued modulation symbols to obtain complex-valued modulation symbols of a corresponding physical channel. For example, the UE processor may obtain complex-valued modulation symbols mapped to subcarriers belong to PDSCH from among complex-valued modulation symbols received in a bandwidth part.

4) Transform De-Precoding

Transform de-precoding (e.g., inverse DFT (IDFT)) is performed on the complex-valued modulation symbols of the uplink physical channel if the transform precoding has been enabled for the uplink physical channel. For the downlink physical channel and for the uplink physical channel for which the transform precoding has been disabled, the transform de-precoding is not performed.

5) Layer De-Mapping.

The complex-valued modulation symbols are de-mapped into one or two codewords.

6) Demodulation and De-Scrambling

The complex-valued modulation symbols of a codeword are demodulated and descrambled into bits of the codeword.

7) Decoding

The codeword is decoded into a transport block. For UL-SCH and DL-SCH, either LDPC base graph 1 or 2 is selected based on the size of the transport block and coding rate R. The codeword may include one or multiple coded blocks. Each coded block is decoded with the selected LDPC base graph into a CRC-attached code block or CRC-attached transport block. If code block segmentation was performed on a CRC-attached transport block at the transmitting side, a CRC sequence is removed from each of CRC-attached code blocks, whereby code blocks are obtained. The code blocks are concatenated into a CRC-attached transport block. The transport block CRC sequence is removed from the CRC-attached transport block, whereby the transport block is obtained. The transport block is delivered to the MAC layer.

In the above described physical layer processing at the transmitting and receiving sides, the time and frequency domain resources (e.g., OFDM symbol, subcarriers, carrier frequency) related to subcarrier mapping, OFDM modulation and frequency up/down conversion can be determined based on the resource allocation (e.g., UL grant, DL assignment).

An RRC state indicates whether an RRC layer of the UE is logically connected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRC connection is established between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in the RRC connected state (RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE). In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced. RRC_INACTIVE may be used for various purposes. For example, the massive machine type communications (MMTC) UEs can be efficiently managed in RRC_INACTIVE. When a specific condition is satisfied, transition is made from one of the above three states to the other.

A predetermined operation may be performed according to the RRC state. In RRC_IDLE, public land mobile network (PLMN) selection, broadcast of system information (SI), cell re-selection mobility, core network (CN) paging and discontinuous reception (DRX) configured by NAS may be performed. The UE shall have been allocated an identifier (ID) which uniquely identifies the UE in a tracking area. No RRC context stored in the BS.

In RRC_CONNECTED, the UE has an RRC connection with the network (i.e., E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is also established for UE. The UE AS context is stored in the network and the UE. The RAN knows the cell which the UE belongs to. The network can transmit and/or receive data to/from UE. Network controlled mobility including measurement is also performed.

Most of operations performed in RRC_IDLE may be performed in RRC_INACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging is performed in RRC_INACTIVE. In other words, in RRC_IDLE, paging for mobile terminated (MT) data is initiated by core network and paging area is managed by core network. In RRC_INACTIVE, paging is initiated by NG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN.

Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRX for RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, in RRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established for UE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knows the RNA which the UE belongs to.

Support of low complexity UEs is described. Section 23.7 of 3GPP TS 36.300 V15.5.0 (2019-03) can be referred.

Low complexity UEs are targeted to low-end (e.g., low average revenue per user, low data rate, delay tolerant) applications, e.g., some machine-type communications.

A low complexity UE has reduced Tx and Rx capabilities compared to other UE of different categories.

A category 0 low complexity UE may access a cell only if SIB1 indicates that access of category 0 UEs is supported. If the cell does not support access of category 0 UEs, the UE considers the cell as barred.

The eNB determines that a UE is a category 0 UE based on the LCID for CCCH and the UE capability.

The S1 signaling has been extended to include the UE radio capability for paging. This paging specific capability information is provided by the eNB to the mobility management entity (MME), and the MME uses this information to indicate to the eNB that the paging request from the MME concerns a low complexity UE.

Support of bandwidth reduced low complexity (BL) UEs is described. Section 23.7a of 3GPP TS 36.300 V15.5.0 (2019-03) can be referred.

A BL UE can operate in any LTE system bandwidth but with a limited channel bandwidth of 6 PRBs (corresponding to the maximum channel bandwidth available in a 1.4 MHz LTE system) in downlink and uplink.

To enable higher data rates, a BL UE can optionally support a larger maximum PDSCH/PUSCH channel bandwidth of 24 PRBs in downlink and a non-BL UE operating in enhanced coverage can optionally support a larger maximum PDSCH/PUSCH channel bandwidth of 24 or 96 PRBs in downlink, and 24 PRBs in uplink in connected mode for unicast transmission.

Table 13 summarizes the maximum PDSCH/PUSCH bandwidth in connected mode for unicast transmission depending on the UE category and enhanced coverage mode. The maximum PDSCH/PUSCH channel bandwidth is configured separately for PDSCH and PUSCH via dedicated RRC signaling.

TABLE 13 UE category/CE mode CE mode A CE mode B BL (Category M1) 6/6 6/6 BL (Category M2) 24/24 24/6  Non-BL 96 (or 24)/24 96 (or 24)/6 (Category 0 and higher)

A category M2 BL UE supports a larger DL and UL maximum transport block size (TBS) for unicast compared to a category M1 BL UE. A category M1 BL UE may support a larger UL maximum TBS size indicated by a separate UE capability.

A BL UE may access a cell only if the master information block (MIB) of the cell indicates that scheduling information for SIB1 specific for BL UEs is scheduled. If not, the UE considers the cell as barred.

A BL UE receives a separate occurrence of system information blocks (sent using different time/frequency resources). A BL UE has a TBS limited to 1000 bit for broadcast. The BL UE determines the scheduling information for SIB1 specific for BL UEs based on information in MIB. Scheduling information for other SIBs is given in SIB1 specific for BL UEs. The BCCH modification period for BL UEs is a multiple of the BCCH modification period provided in SIB2. The SIB transmission occasions within an SI-window are provided in the SIB1 specific for BL UEs. A BL UE can acquire SI messages across SI windows. The maximum number of SI messages that can be acquired across SI windows is 4. A BL UE is not required to detect SIB change when in RRC_CONNECTED.

A BL UE is paged based on paging occasions in time domain, and paging narrowbands in frequency domain. The starting subframe of a paging occasion is determined in the same way as the paging occasion in the legacy paging mechanism.

A set of PRACH resources (e.g., time, frequency, preamble), each associated with BL UEs in normal coverage, is provided in SIB. Number of PRACH repetitions and number of maximum preamble transmission attempts for BL UEs in normal coverage are provided in SIB. Time/frequency resources and repetition factor for random access response messages for BL UEs are derived from the used PRACH resources.

Support of UEs in enhanced coverage is described. Section 23.7b of 3GPP TS 36.300 V15.5.0 (2019-03) can be referred.

A UE in enhanced coverage is a UE that requires the use of enhanced coverage functionality to access the cell. Two enhanced coverage modes (mode A, mode B) are supported. The support of enhanced coverage mode A is mandatory for a BL UE. The maximum PDSCH/PUSCH bandwidth in connected mode for unicast transmission depends on the UE category and enhanced coverage mode as summarized in Table 13 mentioned above.

A UE may access a cell using enhanced coverage functionality only if the MIB of the cell indicates that scheduling information for SIB1 specific for BL UEs is scheduled. System information procedures for UEs in enhanced coverage are identical to the system information procedures for BL UEs. A UE capable of enhanced coverage acquires, if needed, and uses legacy system information when in normal coverage if it is not a BL UE. A UE capable of enhanced coverage acquires, if needed, and uses system information specific for UEs in enhanced coverage. A UE in enhanced coverage is not required to detect SIB change when in RRC_CONNECTED.

A set of PRACH resources (e.g., time, frequency, preamble), each associated with a coverage enhancement level, is provided in SIB. Number of PRACH repetitions and number of maximum preamble transmission attempts per coverage enhancement level are provided in SIB. UEs in same enhanced coverage level use random access resources associated with the same enhanced coverage level. Time/frequency resources and repetition factor for random access response messages for UEs in enhanced coverage are derived from the used PRACH resources.

A UE in enhanced coverage is paged using the same mechanism for paging BL UEs. The starting subframe of a paging occasion and the repetition pattern (in both time and frequency domain for downlink common control signaling) of that paging occasion are determined irrespective of the UEs enhanced coverage level.

The paging request from the MME for a UE supporting enhanced coverage functionality may contain enhanced coverage level related information and corresponding cell ID. If neither the UE Radio Capability for Paging information element (IE) nor the Assistance Data for Paging IE is included in the paging request from the MME, the eNB may need to page the UE in both PDCCH and MPDCCH.

A UE in RRC_IDLE does not inform the network when it changes the enhanced coverage level.

A UE in enhanced coverage camps on a suitable cell where S criterion for UEs in enhanced coverage is fulfilled. The UE shall re-select to inter-frequency cells in which it is able to operate in normal coverage over cells in which it has to be in enhanced coverage.

Connected mode mobility mechanisms such as measurement reporting, network controlled handover, etc., are supported for UEs in enhanced coverage. At handover from a source cell in normal or enhanced coverage mode to a target cell in enhanced coverage mode, the network may provide SIB1-BR to the UE in the handover command. No additional mechanisms are introduced to support the use of enhanced coverage functionality to access an E-UTRA cell during inter-RAT handovers.

Reconfiguration of a UE in connected mode from normal to enhanced coverage mode (and vice versa) is supported by a means of intra-cell handover or RRC configuration without handover.

Narrowband internet-of-things (NB-IoT) is described. Sections 4.10, 5.1.1a, 5.2.1a and 5.2.5a of 3GPP TS 36.300 V15.5.0 (2019-03) can be referred.

NB-IoT provides access to network services using physical layer optimized for very low power consumption (e.g., full carrier bandwidth is 180 kHz, subcarrier spacing can be 3.75 kHz or 15 kHz).

A number of E-UTRA protocol functions supported by all Rel-8 UEs are not used for NB-IoT and need not be supported by eNBs and UEs only using NB-IoT.

The downlink transmission scheme for NB-IoT is based on conventional OFDM using a CP. In the frequency domain, there is one resource block for an NB-IoT carrier, the OFDM sub-carrier spacing Δf=15 kHz always, and in case of frequency division duplex (FDD), only operation with half duplex from NB-IoT UE point of view is supported. There can be more than one NB-IoT carrier configured.

For NB-IoT uplink transmission, both single-tone transmission and multi-tone transmission are defined.

For single-tone transmission, there are two numerologies defined: 3.75 kHz and 15 kHz subcarrier spacing, based on single-carrier FDMA. In the frequency domain, resource blocks are not defined. If the uplink subcarrier spacing Δf=15 kHz, there are 12 consecutive subcarriers. If the uplink subcarrier spacing Δf=3.75 kHz, there are 48 consecutive subcarriers.

Single-tone transmission with 3.75 kHz subcarrier spacing is organized into slots with 2 ms duration, each of which consists of seven symbols located from beginning of the slot. The slot boundary is aligned with subframe boundaries of frame structure type 1. One symbol of 3.75 kHz subcarrier spacing consists of 8448 Ts of symbol with CP length of 256 Ts. The remaining time (2304 Ts) of the slot is used as a guard period.

Multi-tone transmission is based on single-carrier FDMA, with that resource blocks are not defined. There are 12 consecutive uplink subcarriers with uplink subcarrier spacing Δf=15 kHz. The subcarriers can be grouped into sets of 3, 6, or 12 consecutive subcarriers.

A resource unit, schedulable for single-tone NB-Jot PUSCH (NPUSCH) with UL-SCH transmission, is defined as a single 3.75 kHz subcarrier for 32 ms or a single 15 kHz subcarrier for 8 ms. A resource unit, schedulable for multi-tone NPUSCH with UL-SCH transmission is defined as 3 subcarriers for 4 ms; or 6 subcarriers for 2 ms; or 12 subcarriers for 1 ms. A resource unit, schedulable for NPUSCH with ACK/NAK transmission, is defined as a single 3.75 kHz subcarrier for 8 ms or a single 15 kHz subcarrier for 2 ms.

A UL-SCH transport block can be scheduled over one or more than one resource unit in time.

The physical layer random access transmission uses a 3.75 kHz or 1.25 kHz subcarrier spacing and consists of symbol groups with frequency hopping between symbol groups. Each symbol group has a CP and a preamble. Symbol groups with 3.75 kHz subcarrier spacing hop by one or six subcarriers in frequency, and symbol groups with 1.25 kHz subcarrier spacing hop by one, three, or eighteen subcarriers in frequency. Repetitions of groups of symbol groups hop by a pseudo-random number of subcarriers in frequency. There are two in FDD, and four in time division duplex (TDD), possible CP lengths for the random access transmission symbol groups, suitable for different maximum cell sizes.

UE may perform data transmission and/or reception while in RRC_IDLE or RRC_INACTIVE. Considering MTC UE (e.g., BL UE or UE in enhanced coverage), NB-IoT UE, and/or UE supporting 5G NR, UE may perform data transmission and/or reception while in RRC_IDLE or RRC_INACTIVE in a PRB (for NB-IoT UE), in a narrowband (e.g., 6 PRBs for MTC UE), and/or in a BWP (for UE supporting 5G NR). That is, UE may perform data transmission and/or reception while in RRC_IDLE or RRC_INACTIVE only in part of a system bandwidth.

Paging may indicate upcoming data transmission in RRC_IDLE and/or RRC_INACTIVE. However, when UE receives paging indicating data transmission in RRC_IDLE or RRC_INACTIVE, UE may not know how/when UE properly handles SRB/DRB and/or when UE stops receiving data transmission.

The following drawings are created to explain specific embodiments of the present disclosure. The names of the specific devices or the names of the specific signals/messages/fields shown in the drawings are provided by way of example, and thus the technical features of the present disclosure are not limited to the specific names used in the following drawings.

In some implementations, the method in perspective of the wireless device described below may be performed by first wireless device 100 shown in FIG. 2, the wireless device 100 shown in FIG. 3, the first wireless device 100 shown in FIG. 4 and/or the UE 100 shown in FIG. 5.

In some implementations, the method in perspective of the wireless device described below may be performed by control of the processor 102 included in the first wireless device 100 shown in FIG. 2, by control of the communication unit 110 and/or the control unit 120 included in the wireless device 100 shown in FIG. 3, by control of the processor 102 included in the first wireless device 100 shown in FIG. 4 and/or by control of the processor 102 included in the UE 100 shown in FIG. 5.

FIG. 14 shows an example of a method for a wireless device to which implementations of the present disclosure is applied.

In some implementations, the wireless device may be in communication with at least one of a mobile device, a network, and/or autonomous vehicles other than the wireless device.

In step S1400, the wireless device entering an idle state and/or an inactive state.

In step S1410, the wireless device monitors paging.

In step S1420, upon receiving the paging, the wireless device resumes a radio bearer in the idle state and/or the inactive state.

In some implementation, the radio bearer includes at least one of DRB and/or SRB.

In some implementation, the wireless device may receive receiving, from a network, information on a control plane evolved packet system (EPS) optimization and/or a user plane EPS optimization. The wireless device may further receive, from the network, information on which radio bearer should be resumed. The information on the control plane EPS optimization and/or user plane EPS optimization may be received via system information, paging, PDCCH and/or MAC PDU.

For example, in case of the user plane EPS optimization, the wireless device may receive information on which DRB should be resumed for DL transmission. For user plane EPS optimization, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may resume the DRB indicated by the information.

For example, in case of control plane EPS optimization, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may establish a SRB (e.g., SRB1) which is configured for DL transmission.

In some implementation, the paging may indicate that DL data is to be transmitted in the idle state and/or an inactive state, e.g., upcoming DL transmission.

In some implementation, upon receiving the paging, the wireless device transmits a RACH preamble. The wireless device may monitor PDCCH. The wireless device may receive, from a network, DL data, e.g., MAC PDU, scheduled by the PDCCH via PDSCH in the idle state and/or an inactive state based on the resumed radio bearer. The wireless device may transmit, to the network, a HARQ feedback for the DL data via PUCCH.

In some implementation, the radio bearer may be resumed upon transmitting the RACH preamble and/or receiving the PDCCH.

In some implementation, the wireless device may receive, from the network, a timer value. The timer value may be received via system information, paging, PDCCH and/or MAC PDU.

In some implementation, a timer may start based on the timer value upon PDCCH reception, PDSCH reception and/or PUCCH transmission. Upon expiry of the timer, the wireless device may suspend the radio bearer and stop monitoring the PDCCH, In some implementations, after HARQ ACK transmission, after the maximum number of HARQ retransmission is indicated on the PDCCH, and/or if PDCCH or paging indicates stop of the DL transmission, the UE may stop the DL transmission.

FIG. 15 shows an example of a method for performing data transmission for a UE in RRC_IDLE and/or RRC_INACTIVE to which implementations of the present disclosure is applied.

In step S1500, the UE receives paging indicating upcoming DL transmission and a timer value.

In some implementation, the UE may receive receiving, from a network, information on a control plane EPS optimization and/or a user plane EPS optimization. The wireless device may further receive, from the network, information on which radio bearer should be resumed. The information on the control plane EPS optimization and/or user plane EPS optimization may be received via system information, paging, PDCCH and/or MAC PDU.

For example, in case of the user plane EPS optimization, the wireless device may receive information on which DRB should be resumed for DL transmission. For user plane EPS optimization, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may resume the DRB indicated by the information.

For example, in case of control plane EPS optimization, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may establish a SRB (e.g., SRB1) which is configured for DL transmission.

In some implementation, upon receiving the paging, the UE may transmit a RACH preamble and monitor a PDCCH.

In step S1510, the UE resumes a radio bearer. The UE may resume the radio bearer upon receiving the paging or PDCCH and/or upon transmitting the RACH preamble.

In some implementation, the UE may receive PDSCH carrying a MAC PDU via the resumed radio bearer. The UE may send HARQ feedback to the MAC PDU on PUCCH.

In step S1520, the UE starts and/or restarts a timer based on the timer value. The UE may start and/or restart the timer upon PDCCH reception, PDSCH reception, and/or PUCCH transmission.

In step S1530, upon expiry of the timer, the UE suspends the radio bearer and stops monitoring the PDCCH.

According to other implementations of the present disclosure, a method for performing data transmission for a UE in RRC_IDLE or RRC_INACTIVE may include the following steps.

1) The UE receives system information including a list of PUCCH resources.

2) The UE receives paging indicating upcoming DL transmission and a timer value.

In some implementations, the paging may be either a PDCCH addressed to paging RNTI (P-RNTI) or a paging message carried on a PDSCH.

In some implementations, the timer value may be alternatively received from system information, PDCCH and/or the MAC PDU.

3) The UE selects a RACH preamble resource and a random access preamble ID (RAPID). Then, the UE transmits the RACH preamble on a UL frequency band by using the selected RACH preamble resource and the selected RAPID.

4) The UE monitors the PDCCH addressed to a certain RNTI.

In some implementations, the certain RNTI may include C-RNTI or random access RNTI (RA-RNTI).

5) Upon receiving the PDCCH, the UE receives PDSCH carrying a MAC PDU.

6) The UE sends HARQ feedback to the MAC PDU in UL transmission by using the PUCCH resource.

In some implementations, the UL transmission may also include channel quality indicator (CQI) and/or channel state information (CSI). The UL transmission may also include information on UL data volume and/or UL buffer size.

In some implementations, if the UE fails to receive the PDCCH within a time window configured by the base station, the UE may transmit a RACH preamble with a power ramping instead of transmitting the HARQ feedback.

7) Upon PDCCH reception, PDSCH reception, and/or UL transmission (e.g., PUCCH transmission and/or HARQ ACK/NACK transmission), the UE starts and/or restarts a timer. Upon expiry of the timer, the UE stops the DL transmission mode.

Alternatively, after HARQ ACK transmission, after the maximum number of HARQ retransmission is indicated on the PDCCH, and/or if PDCCH or paging indicates stop of the DL transmission mode, the UE may stop the DL transmission mode.

FIG. 16 shows an example of downlink data transmissions for a UE in RRC_IDLE and/or RRC_INACTIVE to which implementations of the present disclosure is applied.

In some implementations, the example shown in FIG. 16 may be applied to a particular DL transmission scheme. For example, the particular DL transmission scheme may include DL early data transmission (EDT).

In some implementations, in the example shown in FIG. 16, the frequency band may correspond to at least one of a PRB (for NB-IoT UE), a narrowband (e.g., 6 PRBs for MTC UE), and/or a BWP (for UE supporting 5G NR).

In some implementations, in the example shown in FIG. 16, the base station may include eNB (for 4G LTE) and/or gNB (for 5G NR).

In step S1600, the UE camps on a cell. In the cell, the UE acquires system information from the base station. The system information may include at least one of the following information for a particular DL transmission scheme.

-   -   Whether DL transmission is available in RRC_IDLE or not     -   Whether DL transmission is available in RRC_INACTIVE or not.     -   A list of DL frequency bands available for DL transmission in         RRC_IDLE and/or RRC_INACTIVE     -   A list of UL frequency bands available for DL transmission in         RRC_IDLE and/or RRC_INACTIVE     -   A list of PUCCH resources used for the particular DL         transmission scheme In step S1602, the UE receives a paging from         the base station.

In some implementations, the paging may be a PDCCH addressed to P-RNTI (e.g., paging indicator) and/or a paging message carried on a PDSCH.

In some implementations, the paging may include RACH preamble information. For example, the RACH preamble information may include RACH resources for upcoming data transmission. The RACH preamble information may include one or more RACH time resources, one or more RACH frequency resources, and/or one or more RAPIDs.

In some implementations, the paging may include an indication on the DL transmission in RRC_IDLE and/or RRC_INACTIVE. For example, the paging may include information on an amount of DL data to be transmitted in RRC_IDLE and/or RRC_INACTIVE.

In some implementations, the paging may include UL timing advance (TA) information and/or PUCCH resource information. The PUCCH resource information may indicate one PUCCH resource from the list of PUCCH resources included in the system information.

In some implementations, the paging may include information on frequency bands (e.g., frequency band index) for upcoming data transmission. Specifically, the base station may select one or more frequency bands from the list of frequency bands indicated by the system information and then may include the selected frequency bands in the paging. The selected frequency bands included in the paging may be only UL frequency bands, only DL frequency bands, and/or both UL frequency bands and DL frequency bands. The frequency band index may indicate one configuration related to a DL/UL frequency band from the list of DL/UL frequency bands.

For example, for NB-IoT UE, the paging may include information on one or more particular PRB as the information on the frequency band. The information on the one or more particular PRB may include a particular PRB index. The particular PRB index may be matched with a PRB configuration indicated by the system information.

For example, for MTC UE, the paging may include information on one or more particular narrowband as the information on the frequency band. The information on the one or more particular narrowband may include a particular narrowband index. The particular narrowband index may be matched with a narrowband configuration indicated by the system information.

For example, for UE supporting 5G NR, the paging may include information on one or more particular BWP as the information on the frequency band. The information on the one or more particular BWP may include a particular BWP index. The particular BWP index may be matched with a BWP configuration indicated by the system information.

In some implementations, the paging may include information one or more beams, e.g., one or more beam indexes such as SS/PBCH block (SSB) index and/or CSI-RS index.

Furthermore, the base station may indicate either the control plane EPS optimization and/or user plane EPS optimization. The control plane EPS optimization and/or user plane EPS optimization may be indicated via system information, paging, PDCCH and/or the MAC PDU. In case of the user plane EPS optimization, the base station may also indicate which DRB should be resumed for DL transmission.

In some implementations, the UE may select a UL frequency band based on the information on the frequency bands received via the paging and/or the list of frequency bands received via the system information.

In some implementations, if the information on the frequency band indicates one UL frequency band, the UE may select the one UL frequency band indicated by the information. In some implementations, if the information on the frequency band indicates more than one UL frequency bands, the UE may select one UL frequency band from the more than one UL frequency bands. The one UL frequency band may be selected from the more than one UL frequency bands based on at least one of random selection, the amount of DL data to be transmitted in RRC_IDLE and/or RRC_INACTIVE, UE ID (such as SAE-temporary mobile subscriber identity (S-TMSI) and/or international mobile subscriber identity (IMSI)) and/or measurement result (such as reference signal received power (RSRP) and/or reference signal received quality (RSRQ)).

In some implementations, the UE may select a RACH resource based on the RACH preamble information received via the paging. For example, the UE may select one of the RACH time resources, one of the RACH frequency resources and/or one of RAPIDs based on at least one of random selection, the amount of DL data to be transmitted in RRC_IDLE and/or RRC_INACTIVE, UE ID (such as S-TMSI and/or IMSI) and/or measurement result (such as RSRP and/or RSRQ).

In step S1604, the UE selects and transmits a RACH preamble by using the selected RACH time/frequency resource and/or the selected RAPID on the selected UL frequency band. In step S1604, the UE transmits a first RACH preamble on the selected UL frequency band.

In some implementations, if the paging may include information one or more beams, e.g., one or more beam indexes such as SS/PBCH block (SSB) index and/or CSI-RS index, the UE may select at least one beam of which measured quality is above a threshold among the one or more beams. Then, the UE may perform contention free random access procedure with the selected beam. If there is no beam of which measured quality is above a threshold, the UE may perform contention based random access procedure by selecting a beam other than the one or more beams.

In some implementations, the UE may determine the RACH time/frequency resource and/or the RAPID based on the UE ID from the RACH time/frequency resources and/or RAPIDs received via the paging.

In some implementations, if the UE receives a certain number via the paging, the UE may determine the RACH time/frequency resource and/or the RAPID based on the UE ID and the certain number. For example, the RAPID may be calculated by the Equation (UE ID×the certain number) mod N, where N is the maximum number of RAPIDs configured for this purpose.

In step S1606, upon receiving the RACH preamble, the base station selects a DL frequency band from the list of DL frequency bands indicated by the system information.

In some implementations, the base station may select a DL frequency band from the list of DL frequency bands based on at least one of at least one of random selection, the amount of DL data to be transmitted in RRC_IDLE and/or RRC_INACTIVE, UE ID (such as S-TMSI and/or IMSI), RACH preamble resource on which the RACH preamble was received, the received RAPID, and/or path loss indicated by the RACH preamble.

In some implementations, the UE may select a DL frequency band based on the information on the frequency bands received via the paging from the list of DL frequency bands indicated by the system information. If the information on the frequency band indicates more than one DL frequency bands, the UE may select one DL frequency band from the more than one DL frequency bands. The one DL frequency band may be selected from the more than one DL frequency bands based on at least one of random selection, the amount of DL data to be transmitted in RRC_IDLE and/or RRC_INACTIVE, the transmitted RAPID, UE ID (such as S-TMSI and/or IMSI) and/or measurement result (such as RSRP and/or RSRQ).

Alternatively, the UE may select the DL frequency band which is matched with the DL frequency band on which the system information and/or the paging is received.

Alternatively, the UE may select the DL frequency band which is matched with the UL frequency band on which the RACH preamble was transmitted.

Alternatively, the UE may select the DL frequency band based on UE ID.

In step S1608, the base station transmits PDCCH on the selected DL frequency band. After transmitting the RACH preamble, the UE may monitor the PDCCH on the selected DL frequency band.

In some implementations, the PDCCH may be addressed to a certain RNTI. For example, the certain RNTI may include C-RNTI and/or RA-RNTI. Alternatively, the certain RNTI may be calculated based on a certain number received via the paging and UE ID. For example, the certain RNTI may be calculated by the Equation (UE ID×the certain number) mod M, where M is the maximum number of RNTI configured for this purpose.

In step S1610, the base station transmits PDSCH carrying a MAC PDU based on the PDCCH.

In some implementations, the PDSCH may be transmitted on the DL frequency band selected based on the PDCCH. Alternatively, the PDSCH may be transmitted on the DL frequency band where the PDCCH is transmitted.

In some implementations, the MAC PDU may include at least a LCID of a logical channel (e.g., a DCCH or a DTCH), and/or a MAC SDU from the logical channel.

In some implementations, the MAC PDU may also include UL TA information in a header of the MAC PDU and/or in a MAC control element (CE) included in the MAC PDU.

In some implementations, the base station may also include a PUCCH resource information in the PDCCH, in a header of the MAC PDU and/or in a MAC CE in the MAC PDU. The PUCCH resource information may indicate one PUCCH resource from the list of PUCCH resources included in the system information.

In step S1612, the UE may fail to receive the PDCCH and so also fail to receive the PDSCH. Thus, the UE transmits a second RACH preamble on the selected UL frequency band again.

In step S1614, the UE receives the PDCCH addressed to a certain RNTI on the selected DL frequency band.

If the UE receives the PDCCH, the UE may receive the PDSCH carrying the MAC PDU on the DL frequency band selected based on the PDCCH. The DL frequency band may be indicated by the PDCCH. Alternatively, the DL frequency band may be same as the DL frequency band where the PDCCH was received.

Alternatively, the UE may select the DL frequency band which is matched with the DL frequency band on which the system information and/or the paging is received.

Alternatively, the UE may select the DL frequency band which is matched with the UL frequency band on which the RACH preamble was transmitted.

Alternatively, the UE may select the DL frequency band based on UE ID.

In step S1618, the UE resumes DRB and/or establishes SRB. The UE configures PUCCH.

In some implementations, for a case that user plane EPS optimization is indicated, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may resume the suspended DRB indicated by the base station.

For a case that control plane EPS optimization is indicated, after reception of the paging, transmission of the RACH preamble and/or reception of the PDCCH addressed to the certain RNTI, the UE may establish a SRB (e.g., SRB1) which is configured with the particular DL transmission mode.

In some implementations, upon receiving the PDSCH, the UE may send HARQ feedback by using a PUCCH resource. The PUCCH resource may be indicated by at least one of the system information, paging, PDCCH and/or the PDSCH, as mentioned in the previous steps. Alternatively, the PUCCH resource may be associated with the selected RACH preamble resource and/or the selected RAPID.

In step S1616, the UE fails to decode the MAC PDU received on the PDSCH.

In step S1620, the UE transmits HARQ NACK by using the PUCCH resource to the base station.

Alternatively, if the UE successfully decodes the MAC PDU received on the PDSCH, the UE may transmit HARQ ACK by using the PUCCH resource to the base station.

In some implementations, the base station may request report of the measurement result to the UE via at least one of the system information, paging, PDCCH and/or PDSCH. If requested by the base station, the UE may measure a DL channel quality after reception of the paging. If requested by the base station, the UE may indicate the measurement result (e.g., CQI, CSI) on the PUCCH, possibly together with HARQ ACK/NACK.

In step S1622, the UE starts (or restarts) a timer. The UE may start (or restart) a timer upon PDCCH reception, PDSCH reception, PUCCH transmission or HARQ ACK/NACK transmission.

In step S1624, the UE transmits Nth RACH preamble on the selected UL frequency band again.

In step S1626, the UE receives the PDCCH addressed to a certain RNTI on the selected DL frequency band.

In step S1628, the UE receives the PDSDH based on the PDCCH, and successfully decodes the MAC PDU received on the PDSCH.

In step S1630, the UE transmits HARQ ACK by using the PUCCH resource to the base station.

In some implementations, if the UE has no data available for uplink transmission and the base station allows the UE to perform uplink transmission with the particular DL transmission mode, the UE may indicate zero data volume and/or L2 buffer size set to zero via the PUCCH. In this case, the UE may immediately stop the particular DL transmission mode.

In some implementations, if the UE has data available for uplink transmission and the base station allows the UE to perform uplink transmission with the particular DL transmission mode, the UE may indicate available data such as data volume and/or L2 buffer size on the PUCCH. Then, upon receiving UL grant from the base station, the UE may perform uplink transmission of a MAC PDU by using the uplink grant. The UE may perform uplink transmission for retransmission of the MAC PDU.

In step S1632, the UE restarts the timer. The UE may restart the timer upon indicating zero data volume and/or L2 buffer size set to zero and/or upon uplink transmission for retransmission of the MAC PDU by using uplink grant.

In step S1634, the timer expires. Upon expiry of the timer, the UE suspends DRB and/or releases SRB, and stops the particular DL transmission mode.

For example, for user plane EPS optimization, if the particular DL transmission stops, the UE may suspend the resumed DRB (and/or all resumed DRBs). For example, for control plane EPS optimization, if the particular DL transmission mode stops, the UE may release the SRB (e.g., SRB1).

Alternatively, after HARQ ACK transmission, after the maximum number of HARQ retransmission is indicated on the PDCCH, and/or if the PDCCH indicates stop of the particular DL transmission mode, the UE may stop the particular DL transmission mode. Or, if the UE receives additional paging indicating stop of the particular DL transmission mode, the UE may stop the particular DL transmission mode.

The present disclosure can have various advantageous effects.

For example, a radio bearer can be resumed for data transmission/reception in an idle state (e.g., RRC_IDLE) and/or an inactive state (e.g., RRC_INACTIVE).

For example, a UE performing DL data reception by using paging can properly start and stop reception of DL data, in particular when connection between the UE and the network is disconnected or suspended.

For example, the system can properly start and stop DL transmission for a UE performing DL data reception based on paging after leaving connected mode, e.g., in an idle state (e.g., RRC_IDLE) and/or an inactive state (e.g., RRC_INACTIVE).

Advantageous effects which can be obtained through specific embodiments of the present disclosure are not limited to the advantageous effects listed above. For example, there may be a variety of technical effects that a person having ordinary skill in the related art can understand and/or derive from the present disclosure. Accordingly, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that may be understood or derived from the technical features of the present disclosure.

Claims in the present disclosure can be combined in a various way. For instance, technical features in method claims of the present disclosure can be combined to be implemented or performed in an apparatus, and technical features in apparatus claims can be combined to be implemented or performed in a method. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in an apparatus. Further, technical features in method claim(s) and apparatus claim(s) can be combined to be implemented or performed in a method. Other implementations are within the scope of the following claims. 

What is claimed is:
 1. A method for a wireless device in a wireless communication system, the method comprising: entering an idle state and/or an inactive state; receiving, from a network, information indicating either a control plane evolved packet system (EPS) optimization or a user plane EPS optimization for downlink transmission; monitoring paging indicating that downlink data is to be transmitted in the idle state and/or an inactive state; based on the information indicating the user plane EPS optimization: upon receiving the paging, resuming at least one of a data radio bearer (DRB) for the downlink transmission in the idle state and/or the inactive state; receiving, from the network, the downlink data via the DRB in the idle state and/or the inactive state; and upon receiving an indication that the downlink transmission is to be stopped, suspending the DRB in the idle state and/or the inactive state; based on the information indicating the control plane EPS optimization: upon receiving the paging, resuming a signaling radio bearer (SRB) for the downlink transmission in the idle state and/or inactive state; receiving, from the network, the downlink data via the SRB in the idle state and/or the inactive state; and upon receiving an indication that the downlink transmission is to be stopped, suspending the SRB in the idle state and/or the inactive state.
 2. The method of claim 1, further comprising receiving, from the network, information that the radio bearer should be resumed.
 3. The method of claim 1, further comprising: receiving, from a network, a timer value.
 4. The method of claim 3, further comprising: monitoring a physical downlink control channel (PDCCH).
 5. The method of claim 4, further comprising: receiving, from a network, downlink data scheduled by the PDCCH via a physical downlink shared channel (PDSCH) in the idle state and/or an inactive state based on the resumed radio bearer.
 6. The method of claim 5, further comprising: transmitting, to the network, hybrid automatic repeat request (HARQ) feedback for the downlink data via a physical uplink control channel (PUCCH).
 7. The method of claim 3, wherein a timer starts based on the timer value upon PDCCH reception, PDSCH reception and/or PUCCH transmission.
 8. The method of claim 7, further comprising: suspending the radio bearer and stopping the monitoring of the PDCCH, upon expiration of the timer.
 9. The method of claim 1, wherein the wireless device is in communication with at least one of a mobile device, a network, and/or autonomous vehicles other than the wireless device.
 10. A wireless device in a wireless communication system, the wireless device comprising: at least one transceiver; at least processor; and at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising: entering an idle state and/or an inactive state; receiving, from a network, information indicating either a control plane evolved packet system (EPS) optimization or a user plane EPS optimization for downlink transmission; monitoring paging indicating that downlink data is to be transmitted in the idle state and/or an inactive state; based on the information indicating the user plane EPS optimization: upon receiving the paging, resuming at least one of a data radio bearer (DRB) for the downlink transmission in the idle state and/or the inactive state; receiving, from the network, the downlink data via the DRB in the idle state and/or the inactive state; and upon receiving an indication that the downlink transmission is to be stopped, suspending the DRB in the idle state and/or the inactive state; based on the information indicating the control plane EPS optimization: upon receiving the paging, resuming a signaling radio bearer (SRB) for the downlink transmission in the idle state and/or inactive state; receiving, from the network, the downlink data via the SRB in the idle state and/or the inactive state; and upon receiving an indication that the downlink transmission is to be stopped, suspending the SRB in the idle state and/or the inactive state. 